Unit & Frequency Converter – LinkZoneTools
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Unit & Frequency Converter — RF Engineering Reference

Power & dB

dBm ↔ Watts ↔ milliwatts
Convert between dBm (decibels relative to 1 milliwatt) and linear power units. Updates live as you type in any field.
dBm
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Watts
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milliwatts (mW)
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microwatts (µW)
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dBW
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Formulas: P(mW) = 10^(dBm/10) · P(W) = P(mW)/1000 · P(µW) = P(mW)×1000 · dBW = dBm − 30
dB Arithmetic Helper
Add or subtract dB values from a starting power level. Useful for applying gains and losses step by step.
Starting Level (dBm)
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Add / Subtract (dB)
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Result (dBm)
Result (mW)
dB ↔ Linear Power Ratio
Convert between dB gain/loss and the corresponding linear power ratio.
dB value
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Linear Power Ratio
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Voltage Ratio
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Power ratio = 10^(dB/10) · Voltage ratio = 10^(dB/20) · dB = 10·log₁₀(power ratio)
EIRP Calculator
Calculate Effective Isotropic Radiated Power — the combination of transmit power, antenna gain, and cable/connector losses.
Tx Power (dBm)
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Antenna Gain (dBi)
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Cable + Connector Loss (dB)
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EIRP (dBm)
EIRP (Watts)
EIRP (dBW)
EIRP (dBm) = Tx Power + Antenna Gain − Cable Loss

Frequency & Wavelength

Frequency ↔ Wavelength
Convert between frequency and wavelength in any unit. Based on speed of light c = 299,792,458 m/s in free space.
Frequency (Hz)
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Frequency (kHz)
Frequency (MHz)
Frequency (GHz)
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Wavelength (m)
Wavelength (cm)
Wavelength (mm)
Period (ns)
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λ = c / f where c = 299,792,458 m/s · Period (s) = 1/f(Hz)
Frequency Band Identifier
Enter a frequency to identify its ITU/IEEE/NATO band designation and common usage.
Frequency (GHz)
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Distance

Distance Converter
Convert between distance units commonly used in wireless link planning. Type in any field.
Kilometers (km)
Miles (mi)
Meters (m)
Feet (ft)
Nautical Miles (NM)
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Inches (in)
Reference: 1 km = 0.62137 mi = 1000 m = 3280.84 ft = 0.53996 NM = 39,370.1 in

Antenna

dBi ↔ dBd Antenna Gain
Convert between dBi (relative to isotropic) and dBd (relative to a half-wave dipole). dBd = dBi − 2.15 dB.
Gain (dBi)
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Gain (dBd)
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Linear Power Ratio
dBd = dBi − 2.15 · A dipole has 2.15 dBi gain over an isotropic radiator
Parabolic Dish — Gain & Beamwidth Estimator
Estimate antenna gain and 3 dB beamwidth for a parabolic dish antenna from its diameter and operating frequency.
Dish Diameter (m)
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Frequency (GHz)
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Efficiency (η)
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Estimated Gain (dBi)
3 dB Beamwidth (°)
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Wavelength (mm)
Gain (dBi) = 10·log₁₀(η · (π·D/λ)²) · HPBW (°) ≈ 70·λ/D · η = aperture efficiency (typically 0.55)

Data Rate & Shannon

Data Rate Converter
Convert between data rate units. Type in any field.
Gbps
Mbps
Kbps
MB/s (Megabytes/sec)
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GB/s (Gigabytes/sec)
1 Gbps = 1000 Mbps = 1,000,000 Kbps · 1 MB/s = 8 Mbps · 1 GB/s = 8 Gbps
Shannon Channel Capacity Estimator
Calculate the theoretical maximum data rate for a channel given its bandwidth and signal-to-noise ratio (SNR). This is the absolute upper limit — real systems achieve 60–85% of Shannon capacity.
Channel Bandwidth (MHz)
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SNR (dB)
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Shannon Capacity (Mbps)
Spectral Efficiency (bps/Hz)
Practical Estimate @70% (Mbps)
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Shannon: C = B · log₂(1 + 10^(SNR/10)) where B is bandwidth in Hz and SNR is linear ratio
Spectral Efficiency Calculator
Calculate spectral efficiency from throughput and channel bandwidth, or vice versa.
Throughput (Mbps)
Bandwidth (MHz)
Spectral Efficiency (bps/Hz)
SE (bps/Hz) = Throughput (bps) / Bandwidth (Hz) · Typical range: 1–10 bps/Hz for real systems

Noise & Sensitivity

Thermal Noise Floor Calculator
Calculate the thermal noise power at the input of a receiver for a given bandwidth and noise figure. This sets the fundamental sensitivity limit of any radio receiver.
Receiver Bandwidth (MHz)
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Noise Figure (dB)
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Temperature (K)
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Thermal Noise (kTB) (dBm)
Noise Floor (kTB + NF) (dBm)
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Min Detectable Signal (0 dB SNR)
kTB (dBm) = 10·log₁₀(k·T·B) + 30 · k = 1.38×10⁻²³ J/K · T in Kelvin · B in Hz
Noise Floor (dBm) = kTB + Noise Figure (dB) · At 290K: kTB ≈ −174 + 10·log₁₀(B_MHz) + 60
Fade Margin → Link Availability Estimator
Estimate annual link availability from fade margin. Based on a simplified flat-fading model — for precise ITU-R availability calculations use a full link budget with ITU-R P.530 methods.
Fade Margin (dB)
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Note: These estimates use a simplified Rayleigh fading approximation. Actual availability depends on path length, frequency, terrain, climate, and k-factor. For licensed microwave design use ITU-R P.530-17 or Vigants-Barnett method.

Cable Loss

Coaxial Cable Loss Estimator
Estimate coaxial cable loss at a given frequency and length. Values are approximate — always check the manufacturer's published attenuation tables for final design. Loss increases with frequency and cable length.
Cable Type
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Frequency (GHz)
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Cable Length (m)
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Total Cable Loss (dB)
Loss per 100m (dB/100m)
Source: Loss coefficients from published manufacturer data sheets (Times Microwave, Andrew/CommScope). Values are approximate — actual loss varies with connector quality, temperature, and cable age. Add ~0.1–0.2 dB per connector.

Recommendation: For links above 2 GHz, keep cable runs under 5m where possible. For runs over 10m at 5+ GHz, use LMR-400 minimum or consider a radio-on-tower installation to eliminate feedline loss entirely.

Propagation & FSPL

Signal Propagation Delay
Calculate one-way and round-trip propagation delay for a wireless link. Based on speed of light in free space (c = 299,792 km/s). Useful for latency budgeting and time-sensitive applications.
Link Distance (km)
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Link Distance (miles)
One-Way Delay (µs)
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One-Way Delay (ms)
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Round-Trip Delay / RTT (µs)
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Round-Trip Delay / RTT (ms)
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Propagation delay = distance / c · c = 299,792 km/s · Note: RF waves travel at approximately the speed of light in free space. In coaxial cable, velocity factor (typically 0.66–0.88) reduces this slightly.
Quick Free Space Path Loss (FSPL)
Fast FSPL calculation without opening the full calculator. Per ITU-R P.525.
Frequency (GHz)
Distance (km)
FSPL (dB)
FSPL (dB) = 20·log₁₀(d_km) + 20·log₁₀(f_GHz) + 92.45 · per ITU-R P.525

⚠ Important — Please Read Before Using This Tool

LinkZoneTools LLC · Unit & Frequency Converter · Terms of Use & Disclaimer

📋 Reference & Educational Use Only

This tool is provided for reference, planning, and educational purposes only. It is not intended to constitute, and shall not be construed as, professional RF engineering advice or a guarantee of wireless link performance. Results are estimates based on theoretical models and published data.

⚠ Tool-Specific Notice — Unit & Frequency Converter

Conversion formulas are based on established physical constants and published ITU standards. Some calculated values (antenna gain estimates, Shannon capacity, cable loss estimates, noise floor) are theoretical approximations. Real-world results will vary based on specific equipment, environmental conditions, and installation quality. Cable loss values are interpolated from published manufacturer data and may not match your specific cable, age, or connector quality.

🌐 Third-Party Data & APIs

Some LinkZoneTools tools use third-party data sources including OpenStreetMap geocoding, Open-Meteo elevation API, OpenTopoData, and ASTER GDEM terrain data. LinkZoneTools LLC does not control these sources and makes no warranty as to their accuracy, availability, or currency.

⚖ Limitation of Liability — No Warranty

LINKZONETOOLS LLC PROVIDES THIS TOOL "AS IS" WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. LINKZONETOOLS LLC SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR EXEMPLARY DAMAGES ARISING FROM USE OF OR RELIANCE ON THIS TOOL, INCLUDING FAILED WIRELESS LINK DEPLOYMENTS, EQUIPMENT LOSSES, LOST REVENUE, OR BUSINESS INTERRUPTION. THE USER ASSUMES ALL RESPONSIBILITY FOR FINAL DESIGN DECISIONS AND THEIR OUTCOMES.

👤 User Responsibility

By using this tool, you acknowledge that: (1) you will independently verify all outputs against current authoritative sources; (2) you will use manufacturer link planning software as the final design authority; (3) you will conduct a physical site survey before specifying equipment or antenna heights; and (4) LinkZoneTools LLC bears no responsibility for any errors, omissions, or outcomes resulting from use of this tool.

LinkZoneTools LLC · Sarasota, FL · linkzonetools.com
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📅 Tool last reviewed: June 2026
⚠ Reference & Educational Use Only — Calculated values are theoretical approximations. Real-world performance varies. Cable loss values interpolated from published data — verify against your specific cable datasheet. LinkZoneTools LLC makes no warranty as to accuracy. 📅 Last reviewed: June 2026

📚 How the Unit Converter Works

What does this tool do?

RF engineering uses a lot of different units — dBm, mW, GHz, MHz, dBi. This tool converts between them all and serves as a quick reference for key formulas used in wireless link planning.

The sections

Use the list on the left (or the dropdown on mobile) to move between the eight reference sections:

  • Power & dB: Convert between dBm, watts, milliwatts
  • Frequency & Wavelength: GHz, MHz, Hz, and wavelength
  • Distance: km, miles, feet, nautical miles
  • Antenna: Calculate dish gain and beamwidth
  • Data Rate & Shannon: Theoretical maximum throughput
  • Noise & Sensitivity: Thermal noise and receiver sensitivity
  • Cable Loss: Coaxial feedline attenuation reference
  • Propagation & FSPL: Quick path loss and delay calculations
💡 Pro tip: Use "Export Reference Card" at the bottom of the section list to generate a printable PDF with all formulas and conversion tables.